.\" $OpenBSD: rtwn.4,v 1.2 2015/07/09 11:28:53 stsp Exp $
.\"
.\" Copyright (c) 2010 Damien Bergamini <damien.bergamini@free.fr>
.\" Copyright (c) 2015 Stefan Sperling <stsp@openbsd.org>
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
.\"
.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.Dd $Mdocdate: July 9 2015 $
.Dt RTWN 4
.Os
.Sh NAME
.Nm rtwn
.Nd Realtek RTL8188CE PCIe IEEE 802.11b/g/n wireless network device
.Sh SYNOPSIS
.Cd "rtwn* at pci? port ?"
.Sh DESCRIPTION
The
.Nm
driver supports PCIe wireless network devices based on the Realtek
RTL8188CE chipset.
.Pp
The RTL8188CE is a highly integrated 802.11n adapter that combines a MAC,
a 1T1R capable baseband and an RF in a single chip.
It operates in the 2GHz spectrum only.
.Pp
These are the modes the
.Nm
driver can operate in:
.Bl -tag -width "IBSS-masterXX"
.It BSS mode
Also known as
.Em infrastructure
mode, this is used when associating with an access point, through
which all traffic passes.
This mode is the default.
.It monitor mode
In this mode the driver is able to receive packets without
associating with an access point.
This disables the internal receive filter and enables the card to
capture packets from networks which it wouldn't normally have access to,
or to scan for access points.
.El
.Pp
The
.Nm
driver can be configured to use
Wired Equivalent Privacy (WEP) or
Wi-Fi Protected Access (WPA-PSK and WPA2-PSK).
WPA is the current encryption standard for wireless networks.
It is strongly recommended that WEP
not be used as the sole mechanism
to secure wireless communication,
due to serious weaknesses in it.
.Pp
The
.Nm
driver can be configured at runtime with
.Xr ifconfig 8
or on boot with
.Xr hostname.if 5 .
.Sh FILES
The driver needs at least version 1.0 of the following firmware files,
which are loaded when an interface is brought up:
.Pp
.Bl -tag -width Ds -offset indent -compact
.It /etc/firmware/rtwn-rtl8192cfwU
.It /etc/firmware/rtwn-rtl8192cfwU_B
.El
.Pp
A prepackaged version of the firmware can be installed using
.Xr fw_update 1 .
.Sh EXAMPLES
The following example scans for available networks:
.Pp
.Dl # ifconfig rtwn0 scan
.Pp
The following
.Xr hostname.if 5
example configures rtwn0 to join network
.Dq mynwid ,
using WPA key
.Dq mywpakey ,
obtaining an IP address using DHCP:
.Bd -literal -offset indent
nwid mynwid
wpakey mywpakey
dhcp
.Ed
.Sh DIAGNOSTICS
.Bl -diag
.It "rtwn0: could not read firmware ..."
For some reason, the driver was unable to read the microcode file from the
filesystem.
The file might be missing or corrupted.
.It "rtwn0: device timeout"
A frame dispatched to the hardware for transmission did not complete in time.
The driver will reset the hardware.
This should not happen.
.El
.Sh SEE ALSO
.Xr arp 4 ,
.Xr ifmedia 4 ,
.Xr intro 4 ,
.Xr netintro 4 ,
.Xr pci 4 ,
.Xr hostname.if 5 ,
.Xr ifconfig 8
.Sh HISTORY
The
.Nm
driver first appeared in
.Ox 5.8 .
.Sh AUTHORS
The
.Nm
driver was written by
.An -nosplit
.An Stefan Sperling Aq Mt stsp@openbsd.org .
It was based on the
.Xr urtwn 4
driver written by
.An Damien Bergamini Aq Mt damien.bergamini@free.fr .
.Sh CAVEATS
The
.Nm
driver does not support any of the 802.11n capabilities offered by the
adapters.
Additional work is required in
.Xr ieee80211 9
before those features can be supported.
